Hollow Earth Festival

Start: Saturday, April 25, 2026 1:00PM
End: Saturday, April 25, 2026 7:00PM

Join us at the site of the Hollow Earth Monument in Hamilton! Ohio (Butler County) for a fun-filled, experiential day where history and science collide! Each year we throw a festival to celebrate Hamiltonians that were visionaries and veterans that inspired so many in our city and beyond. Our visionary icon is John Symmes: a Hamilton visionary that inspired the sci-fi genre. We celebrate all things interesting, unique, and fun about Hamilton, raising funds to support the park and help protect and maintain the monument, a tourist destination for wanderers that navigate via Atlas Obscura. This year, as an official Ohio 250th celebration, we'll showcase entertainment and special event features like: Hot air balloon with Askren Hot Air Balloon Team! Experience the Hollow Earth ball exhibit! Be amazed by circus performers like Kiri Ann and magician Doug Nagel! Run around in a hamster ball, or play the free games for all ages! Unique vendors like crack open your own geode or join the scavenger hunt! Touch a truck with City of Hamilton Infrastructure! Make your own human-powered smoothie - with Hamilton Urban Garden Systems (HUGS)! Express your creative side and paint a mural! Artists painting live on site! And much more! Live music from: The Dad Bods Acoustic, Superhound, and The AmpFibians! KidsZone with a fossil dig activity, Miami University STEAM Studio, Facepainting by Chaka Lynn. And for adults, a specially brewed Earth Donut Belgian beer by Municipal Brew Works. Food trucks including: Bliss & Nosh Charcuterie, Chester's Pizza, Tuesday's Tacos & Churros, and Peace, Love, & Mini-Donuts.